Cervical ripening, or opening of the cervix prior to the onset of labor, is under hormonal control. Failure of the cervix to ripen at term increases the chance of delivery problems, including the need for cesarean section. Further consequences include prolonged hospital stays, increased medical costs, and an overall increase in maternal and fetal morbidity. There are several devices and methods presently utilized to induce artificially the ripening of the cervix to prevent pregnancy complications. One of the most widely used methods involves the intravenous administration of oxytocin. This method, however, causes a prolonged period of induction, tends to suffer from a large failure rate, and may cause patient discomfort. Other common methods of inducing labor include administration of prostaglandin (PG), either systemically or by topical application. Like oxytocin, PG may cause certain undesirable side effects, such as nausea, vomiting, and uterine hypertoxicity.
Mechanical methods of inducing ripening include the use of balloon catheters and hygroscopic cervical dilators. Such devices have the advantage of causing a gradual cervical dilation and minimizing patient discomfort. Several types of catheters have been utilized for this purpose. One example is that disclosed in U.S. Pat. No. 4,976,692 to Atad et al., showing a two balloon catheter that is placed such that one balloon is in the uterus, and the other balloon is in the vagina. Each balloon connects separately to flexible tubing, permitting independent filling or emptying of each balloon. This particular catheter also has a third flexible tube that allows injection of pharmaceutical agents through a gap between both balloons, or inside the cervix. However, this catheter requires manipulation and adjustment of three different valves arranged in a cumbersome fashion. Moreover, the administration of pharmaceutical agents in the cervical area through this catheter may fail to deliver the entire dose, as the agents must travel from the valve through the tube to the discharge site.
Thus, there is a need for a simple yet effective product to use in the ripening of the cervix and inducement of labor.